1. Field of the Invention
The invention relates to an electrochemical storage cell of the alkali metal and chalcogen type with at least one anode space to receive the anolyte and a cathode space intended to receive the catholyte. The spaces are separated from each other by an alkali ion-conducting solid electrolyte and are confined, at least in some regions, by a metallic housing. The solid electrolyte is cup-shaped, and is connected at its open end to at least one ring-shaped insulating body in a force-locking manner. A rod-shaped current collector which protrudes to the outside goes through the lid of the storage cell and extends into its interior.
2. Summary of the Invention
Such rechargeable electrochemical storage cells with a solid electrolyte are highly suitable for constructing storage batteries with high energy and power density. The solid electrolytes which are used in the alkali/chalcogen storage cells and are made, for instance, of .beta.-aluminum oxide, are distinguished by the feature that the partial conductivity of the mobile ion is very high and the partial conductivity of the electrons is smaller by many powers of ten. The use of such solid electrolytes for the construction of electrochemical storage cells, results in practically no self-discharge taking place because the electron conductivity is negligible and the reaction substances also cannot penetrate the solid electrolyte as neutral particles.
A specific example of such rechargeable electrochemical storage cells are those of the sodium and sulfur type, with the solid electrolyte made of .beta.-aluminum oxide. One advantage of these electrochemical storage cells is that no secondary reactions occur during the charging of the storage cells. The reason for this is again that only one kind of ions can get through the solid electrolyte. The current yield of such a sodium/sulfur storage cell is therefore approximately 100%. In these electrochemical storage cells the ratio of the energy content to the total weight of such a storage cell as compared to a lead storage cell is very large since the reaction substances are light, and much energy is released in the electrochemical reaction. Therefore, electrochemical storage cells of the sodium and sulfur type have considerable advantages over conventional storage batteries such as lead storage batteries.
A disadvantage of these electrochemical storage cells is that they must be kept at high operating temperatures of about 300.degree. to 500.degree. C. for charging them, so that the chemical reactions required therefor can proceed in the desired manner. At these temperatures, considerable problems arise with the materials used. In particular, incompatibilities occur between the materials which are used for the manufacture of the storage cell and the reactants, especially the sodium and the sulfur. In the vicinity of the closure of this storage cell in which the openings of the two reactant spaces are adjacent to each other, corrosion phenomena appear in spite of the fact that these spaces are carefully sealed against each other.
An electrochemical storage cell is described in German Patent Application No. P 30 33 438.4, in which the thermo-compression method was used for making the cell closure. It is a disadvantage here that for making this closure, the annular space between the metallic housing and the solid electrolyte must be made wider than normal because the closure part outside the solid electrolyte itself is very wide.